Matt Ranostay | 466df4d | 2015-12-05 22:58:22 -0800 | [diff] [blame] | 1 | /* |
| 2 | * ams-iaq-core.c - Support for AMS iAQ-Core VOC sensors |
| 3 | * |
| 4 | * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | */ |
| 17 | |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/mutex.h> |
| 20 | #include <linux/init.h> |
| 21 | #include <linux/i2c.h> |
| 22 | #include <linux/iio/iio.h> |
| 23 | |
| 24 | #define AMS_IAQCORE_DATA_SIZE 9 |
| 25 | |
| 26 | #define AMS_IAQCORE_VOC_CO2_IDX 0 |
| 27 | #define AMS_IAQCORE_VOC_RESISTANCE_IDX 1 |
| 28 | #define AMS_IAQCORE_VOC_TVOC_IDX 2 |
| 29 | |
| 30 | struct ams_iaqcore_reading { |
| 31 | __be16 co2_ppm; |
| 32 | u8 status; |
| 33 | __be32 resistance; |
| 34 | __be16 voc_ppb; |
| 35 | } __attribute__((__packed__)); |
| 36 | |
| 37 | struct ams_iaqcore_data { |
| 38 | struct i2c_client *client; |
| 39 | struct mutex lock; |
| 40 | unsigned long last_update; |
| 41 | |
| 42 | struct ams_iaqcore_reading buffer; |
| 43 | }; |
| 44 | |
| 45 | static const struct iio_chan_spec ams_iaqcore_channels[] = { |
| 46 | { |
| 47 | .type = IIO_CONCENTRATION, |
| 48 | .channel2 = IIO_MOD_CO2, |
| 49 | .modified = 1, |
| 50 | .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), |
| 51 | .address = AMS_IAQCORE_VOC_CO2_IDX, |
| 52 | }, |
| 53 | { |
| 54 | .type = IIO_RESISTANCE, |
| 55 | .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), |
| 56 | .address = AMS_IAQCORE_VOC_RESISTANCE_IDX, |
| 57 | }, |
| 58 | { |
| 59 | .type = IIO_CONCENTRATION, |
| 60 | .channel2 = IIO_MOD_VOC, |
| 61 | .modified = 1, |
| 62 | .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), |
| 63 | .address = AMS_IAQCORE_VOC_TVOC_IDX, |
| 64 | }, |
| 65 | }; |
| 66 | |
| 67 | static int ams_iaqcore_read_measurement(struct ams_iaqcore_data *data) |
| 68 | { |
| 69 | struct i2c_client *client = data->client; |
| 70 | int ret; |
| 71 | |
| 72 | struct i2c_msg msg = { |
| 73 | .addr = client->addr, |
| 74 | .flags = client->flags | I2C_M_RD, |
| 75 | .len = AMS_IAQCORE_DATA_SIZE, |
| 76 | .buf = (char *) &data->buffer, |
| 77 | }; |
| 78 | |
| 79 | ret = i2c_transfer(client->adapter, &msg, 1); |
| 80 | |
| 81 | return (ret == AMS_IAQCORE_DATA_SIZE) ? 0 : ret; |
| 82 | } |
| 83 | |
| 84 | static int ams_iaqcore_get_measurement(struct ams_iaqcore_data *data) |
| 85 | { |
| 86 | int ret; |
| 87 | |
| 88 | /* sensor can only be polled once a second max per datasheet */ |
| 89 | if (!time_after(jiffies, data->last_update + HZ)) |
| 90 | return 0; |
| 91 | |
| 92 | ret = ams_iaqcore_read_measurement(data); |
| 93 | if (ret < 0) |
| 94 | return ret; |
| 95 | |
| 96 | data->last_update = jiffies; |
| 97 | |
| 98 | return 0; |
| 99 | } |
| 100 | |
| 101 | static int ams_iaqcore_read_raw(struct iio_dev *indio_dev, |
| 102 | struct iio_chan_spec const *chan, int *val, |
| 103 | int *val2, long mask) |
| 104 | { |
| 105 | struct ams_iaqcore_data *data = iio_priv(indio_dev); |
| 106 | int ret; |
| 107 | |
| 108 | if (mask != IIO_CHAN_INFO_PROCESSED) |
| 109 | return -EINVAL; |
| 110 | |
| 111 | mutex_lock(&data->lock); |
| 112 | ret = ams_iaqcore_get_measurement(data); |
| 113 | |
| 114 | if (ret) |
| 115 | goto err_out; |
| 116 | |
| 117 | switch (chan->address) { |
| 118 | case AMS_IAQCORE_VOC_CO2_IDX: |
| 119 | *val = 0; |
| 120 | *val2 = be16_to_cpu(data->buffer.co2_ppm); |
| 121 | ret = IIO_VAL_INT_PLUS_MICRO; |
| 122 | break; |
| 123 | case AMS_IAQCORE_VOC_RESISTANCE_IDX: |
| 124 | *val = be32_to_cpu(data->buffer.resistance); |
| 125 | ret = IIO_VAL_INT; |
| 126 | break; |
| 127 | case AMS_IAQCORE_VOC_TVOC_IDX: |
| 128 | *val = 0; |
| 129 | *val2 = be16_to_cpu(data->buffer.voc_ppb); |
| 130 | ret = IIO_VAL_INT_PLUS_NANO; |
| 131 | break; |
| 132 | default: |
| 133 | ret = -EINVAL; |
| 134 | } |
| 135 | |
| 136 | err_out: |
| 137 | mutex_unlock(&data->lock); |
| 138 | |
| 139 | return ret; |
| 140 | } |
| 141 | |
| 142 | static const struct iio_info ams_iaqcore_info = { |
| 143 | .read_raw = ams_iaqcore_read_raw, |
| 144 | .driver_module = THIS_MODULE, |
| 145 | }; |
| 146 | |
| 147 | static int ams_iaqcore_probe(struct i2c_client *client, |
| 148 | const struct i2c_device_id *id) |
| 149 | { |
| 150 | struct iio_dev *indio_dev; |
| 151 | struct ams_iaqcore_data *data; |
| 152 | |
| 153 | indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); |
| 154 | if (!indio_dev) |
| 155 | return -ENOMEM; |
| 156 | |
| 157 | data = iio_priv(indio_dev); |
| 158 | i2c_set_clientdata(client, indio_dev); |
| 159 | data->client = client; |
| 160 | |
| 161 | /* so initial reading will complete */ |
| 162 | data->last_update = jiffies - HZ; |
| 163 | mutex_init(&data->lock); |
| 164 | |
| 165 | indio_dev->dev.parent = &client->dev; |
| 166 | indio_dev->info = &ams_iaqcore_info, |
| 167 | indio_dev->name = dev_name(&client->dev); |
| 168 | indio_dev->modes = INDIO_DIRECT_MODE; |
| 169 | |
| 170 | indio_dev->channels = ams_iaqcore_channels; |
| 171 | indio_dev->num_channels = ARRAY_SIZE(ams_iaqcore_channels); |
| 172 | |
| 173 | return devm_iio_device_register(&client->dev, indio_dev); |
| 174 | } |
| 175 | |
| 176 | static const struct i2c_device_id ams_iaqcore_id[] = { |
| 177 | { "ams-iaq-core", 0 }, |
| 178 | { } |
| 179 | }; |
| 180 | MODULE_DEVICE_TABLE(i2c, ams_iaqcore_id); |
| 181 | |
| 182 | static const struct of_device_id ams_iaqcore_dt_ids[] = { |
| 183 | { .compatible = "ams,iaq-core" }, |
| 184 | { } |
| 185 | }; |
| 186 | MODULE_DEVICE_TABLE(of, ams_iaqcore_dt_ids); |
| 187 | |
| 188 | static struct i2c_driver ams_iaqcore_driver = { |
| 189 | .driver = { |
| 190 | .name = "ams-iaq-core", |
| 191 | .of_match_table = of_match_ptr(ams_iaqcore_dt_ids), |
| 192 | }, |
| 193 | .probe = ams_iaqcore_probe, |
| 194 | .id_table = ams_iaqcore_id, |
| 195 | }; |
| 196 | module_i2c_driver(ams_iaqcore_driver); |
| 197 | |
| 198 | MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>"); |
| 199 | MODULE_DESCRIPTION("AMS iAQ-Core VOC sensors"); |
| 200 | MODULE_LICENSE("GPL v2"); |